3.2.2. Morphological analysis of foramen magnum in African
small Pangolin (P. tricuspis) in stepwise reconstruction
Stepwise foramen magnum outline reconstruction in P. tricspisrevealed better accuracy with increasing harmonic numbers from the
1st to 14th as presented visually in
Fig. 5. The accuracy of this as shown by the fit index of original vs
reconstructed values is about 97% (Fig. 6). Fifty-two (52) principal
components coefficients were analyzed with 14 harmonics with a total
variance of 1.276294E-001, the first 4 principal components yielded
effective description of the foramen outlines (Table 6).
Figure 5 Contour reconstructions of the foramen magnum outlines
in Small African Pangolins (P. tricuspis ) for the first 14
harmonics (Overlapped reconstructions -2std= +std Red, mean is green,
-std yellow)
Figure 6 Allometric analysis of the foramen magnum outline
(P.tricuspis ) in caudal view showing fit diagram of incremental
EF harmonics evaluated from discriminant analysis
A full morphologic description of the outlines was achieved in evaluated
samples by the 5th harmonic followed by finer details
from the 6th to 14th harmonic. The
first portion to be morphologically characterized from a graphic central
point was the direct dorsal and ventral rims in a clockwise direction by
the 1st harmonic, the left dorsolateral aspect in
caudal perspective in relation to the central point was perfectly
elucidated by PC2 whereas PC3 explained the right dorso-lateral and left
ventro-lateral aspects at the condylar rims, the 4thharmonic was more diffuse and at variance focusing on the right and left
lateral rims (Figs. 2b and 5). The last parts to be reconstructed were
the left dorso-lateral left lateral and left ventro-lateral rims in a
dorso-ventral direction (5th - 14thharmonics). Components of its asymmetry were observed by the
5th harmonic accurately. Variance-covariance matrix
along ontogenetic lines was between 0.0017 and 0.56, discriminant
analysis in ontogeny of the sample population in stepwise harmonic
increments and Mahalanobis distance (Fig. 6) demonstrated gradient
decline in distance with elliptical Fourier harmonics.
Sample proportion demonstrating significant size and shape differences
before was (82.3%) and (8.2%) after size normalization thus yielding
74.1% accuracy decline with size factor elimination employing size
normalization (Table 7) protocol revealed shape an overriding factor.
This finding satisfies the third (3rd) hypothesis of
association stated for this investigation